Add onion and garlic to pot and saute until tender, about 3 minutes. Add wine and cook over high heat until reduced by half. Add stock, bring to a boil and add chicken. Cover and reduce heat to medium. Cook 35 minutes. Add potatoes, celery and bell peppers. Cover and cook 25 minutes longer or until potatoes and carrots are tender.

Meanwhile, make dumplings by sifting together flour, baking powder and salt. In a large bowl, combine milk, oil, herbs and cheese. Gradually add flour mixture, stirring just until dough is moist. Stir mushrooms and zucchini into bubbling stew. Drop tablespoons of dough unto the surface of stew. Cover and allow to cook another 15 minutes. Serve immediately.